CODEWITHSUNDEEP
pythonpandasnumpy
rpb
rpb

Reputation: 3299

Getting Error: "ValueError: If using all scalar values, you must pass an index" when converting ndarray to pandas Dataframe

When transforming multiple ndarray to a df as per the code below

import  numpy as np
import pandas as pd

ls_a = ['TA', 'BAT', 'T']
xxx = ['xx', 'cc']

feature_no = len(ls_a)
windows_no = len(xxx)


sub_iti = np.repeat([['s1']], (feature_no * windows_no), axis=0).reshape(-1, 1)
tw = np.repeat([xxx], feature_no, axis=1).reshape(-1, 1)
col_iti = np.repeat([ls_a], windows_no, axis=0).reshape(-1, 1)

df=pd.DataFrame ({'sub_iti': sub_iti,'tw': tw,'col_iti': col_iti})

, the compiler return an error

ValueError: If using all scalar values, you must pass an index

Based on OP, the argument index was inputed as below

 df=pd.DataFrame (
             {'sub_iti': sub_iti,
              'tw': tw,
              'col_iti': col_iti},index=range(0,3*2) )

However, the compiler return diff rent error

Exception: Data must be 1-dimensional

May I know how to address this issue?

Upvotes: 1

Views: 7996

Answers (1)

Quang Hoang
Quang Hoang

Reputation: 150785

All of your sub_iti, tw, col_iti are 2D numpy arrays. However, when you do:

df=pd.DataFrame ({'sub_iti': sub_iti,
                   'tw': tw,
                   'col_iti': col_iti} )

Pandas expected them to be 1D numpy arrays or lists, since that's how columns of a DataFrame should be. You can try:

df=pd.DataFrame ({'sub_iti': sub_iti.tolist(),
                 'tw': tw.tolist(),'col_iti': col_iti.tolist()})

Output:

  sub_iti    tw col_iti
0    [s1]  [xx]    [TA]
1    [s1]  [xx]   [BAT]
2    [s1]  [xx]     [T]
3    [s1]  [cc]    [TA]
4    [s1]  [cc]   [BAT]
5    [s1]  [cc]     [T]

But I do think that you should remove the lists inside each cell, and use ravel() instead of tolist():

df=pd.DataFrame ({'sub_iti': sub_iti.ravel(),
                 'tw': tw.ravel(),'col_iti': col_iti.ravel()})

Output:

  sub_iti  tw col_iti
0      s1  xx      TA
1      s1  xx     BAT
2      s1  xx       T
3      s1  cc      TA
4      s1  cc     BAT
5      s1  cc       T

Upvotes: 1

Related Questions